a solemn ceremony, chiefly among Reform and Conservative Jews, that is held in the synagogue on Friday night or Saturday morning to admit formally as an adult member of the Jewish community a girl 12 to 13 years old.

An important ceremony and social event in Judaism marking the beginning of religious responsibility for Jewish girls; it is the less frequently observed counterpart of the bar mitzvah. Bat mitzvah is Hebrew for “daughter of the commandment.”